On Fri, 29 Dec 2023, Tamar Christina wrote:
> Hi All,
>
> We can't support nonlinear inductions other than neg when vectorizing
> early breaks and iteration count is known.
>
> For early break we currently require a peeled epilog but in these cases
> we can't compute the remaining values.
>
> Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> tested on cross cc1 for amdgcn-amdhsa and issue fixed.
>
> Ok for master?
>
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> PR middle-end/113163
> * tree-vect-loop-manip.cc (vect_can_peel_nonlinear_iv_p):
Misses sth.
> gcc/testsuite/ChangeLog:
>
> PR middle-end/113163
> * gcc.target/gcn/pr113163.c: New test.
>
> --- inline copy of patch --
> diff --git a/gcc/testsuite/gcc.target/gcn/pr113163.c
> b/gcc/testsuite/gcc.target/gcn/pr113163.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..99b0fdbaf3a3152ca008b5109abf6e80d8cb3d6a
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/gcn/pr113163.c
> @@ -0,0 +1,30 @@
> +/* { dg-do compile } */
> +/* { dg-additional-options "-O2 -ftree-vectorize" } */
> +
> +struct _reent { union { struct { char _l64a_buf[8]; } _reent; } _new; };
> +static const char R64_ARRAY[] =
> "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
> +char *
> +_l64a_r (struct _reent *rptr,
> + long value)
> +{
> + char *ptr;
> + char *result;
> + int i, index;
> + unsigned long tmp = (unsigned long)value & 0xffffffff;
> + result =
> + ((
> + rptr
> + )->_new._reent._l64a_buf)
> + ;
> + ptr = result;
> + for (i = 0; i < 6; ++i)
> + {
> + if (tmp == 0)
> + {
> + *ptr = '\0';
> + break;
> + }
> + *ptr++ = R64_ARRAY[index];
> + tmp >>= 6;
> + }
> +}
> diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
> index
> 3810983a80c8b989be9fd9a9993642069fd39b99..f1bf43b3731868e7b053c186302fbeaf515be8cf
> 100644
> --- a/gcc/tree-vect-loop-manip.cc
> +++ b/gcc/tree-vect-loop-manip.cc
> @@ -2075,6 +2075,22 @@ vect_can_peel_nonlinear_iv_p (loop_vec_info loop_vinfo,
> return false;
> }
>
> + /* We can't support partial vectors and early breaks with an induction
> + type other than add or neg since we require the epilog and can't
> + perform the peeling. PR113163. */
> + if (LOOP_VINFO_EARLY_BREAKS (loop_vinfo)
> + && LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant ()
But why's that only for constant VF? We might never end up here
with variable VF but the check looks odd ...
OK with that clarified and/or the test removed.
Thanks,
Richard.
> + && LOOP_VINFO_USING_PARTIAL_VECTORS_P (loop_vinfo)
> + && induction_type != vect_step_op_neg)
> + {
> + if (dump_enabled_p ())
> + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
> + "Peeling for epilogue is not supported"
> + " for nonlinear induction except neg"
> + " when iteration count is known and early breaks.\n");
> + return false;
> + }
> +
> return true;
> }
>
>
>
>
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
